1. Field Of The Invention
The present invention relates to packers for use in well bores, and more particularly, to a packer which allows manipulation of a tool below the packer by some reciprocation of the tool string without setting the packer.
2. Description Of The Prior Art
A multiple purpose retrievable packer designed for testing, treating and squeezing operations in a well bore is the Champ.RTM. III packer. This packer is set by turning the work string to the right and setting down weight. Pressure applied below the packer forces hydraulic holddown slips against the casing. This helps prevent the packer from being pumped up the well bore. A straight upward pull releases the packer.
A concentric bypass is built into the Champ.RTM. III packer, and this allows the fluid to bypass between two concentric mandrels, requiring all circulated fluid to go around the bottom of the packer. The bypass is locked in the open position and cannot close until the setting action engages the lower mechanical slips. A large area through the bypass allows the packer to be run with a minimum of pressure surges being created. A pressure balancing system helps prevent the bypass from being pumped open.
The Champ.RTM. III packer has a relatively short setting stroke, and a portion of the outer housing forms an upper packer shoe. When weight is set down, the bypass is closed, and the shoe is forced downwardly against the packer elements squeezing them outwardly into a sealing position. At approximately the same time, the mechanical slips are forced outwardly to grippingly engage the well bore. Because of the relatively short setting stroke, manipulation of certain tools such as the Halliburton Services FO Frac System is not possible with this packer. Accordingly, there is a need for a packer such as the Champ.RTM. III packer with a relatively longer stroke which allows some manipulation of the tool string to actuate certain tools below the packer.
The long stroke packer of the present invention meets the above-described need by providing a modification of the Champ.RTM. III packer and adds length to the setting stroke thereof.